[FLINK-30329] flink-kubernetes-operator helm chart does not work with dynamic config because of use of volumeMount subPath

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: kubernetes-operator-1.4.0, kubernetes-operator-1.3.1
• Component/s: Kubernetes Operator
• Labels: pull-request-available
• Assignee: Andrew Otto
• Reporter: Andrew Otto
• Created: 07/Dec/22 19:42
• Updated: 28/Aug/23 07:35
• Resolved: 12/Dec/22 15:52

Description

flink-kubernetes-operator supports dynamic configuration when kubernetes.operator.dynamic.config.enabled is enabled.  The provided helm charts make use of a k8s ConfigMap to provide the flink-conf.yaml file.  These helm charts make use of the subPath VolumeMount feature.  When mounted volumes use subPath, the volume that uses them is not updated automatically.  So, even you do update the ConfigMap in k8s, the flink-conf.yaml file will never see those updates.

• https://kubernetes.io/docs/concepts/configuration/configmap/#mounted-configmaps-are-updated-automatically
• https://kubernetes.io/docs/concepts/storage/volumes/#configmap

Since all 'subPaths' of the volume are being mounted in both the operator and webhook containers at the same paths, I believe an easy fix would be to avoid declaring individual volumeMounts for each file, and just mount the whole ConfigMap as a volume at /opt/flink/conf.

Issue Links

• links to: GitHub Pull Request #478
• links to: GitHub Pull Request #494